Field of the Invention
The invention relates to a method and a device for driving at least one capacitive actuator, in particular a piezoelectrically operated fuel injection valve of an internal combustion engine.
Piezoelectric actuators contain a multiplicity of piezoceramic layers, and form a so-called stack, which upon the application of a voltage changes its dimensions, in particular its length s by a deviation ds, or generates an electric voltage in the event of a mechanical compression or tension.
Published, Non-Prosecuted German Patent Application DE 41 22 984 A1 discloses a driving device for a piezoelectric element in which the driving of the piezoelectric element is performed via corresponding electronic switches having prescribed charging and discharging times.
Published, Non-Prosecuted German Patent Application 196 32 872.1 A, corresponding to U.S. patent application Ser. No. 09/250,875, filed on Feb. 16, 1999, has already proposed a method for driving a capacitive actuator, in accordance with which the actuator is charged with a prescribed charging voltage until the voltage measured at the actuator during the driving operation reaches a prescribed value.